Stitch-forming mechanism for sewing-machines



J. A. FLANAGAN.

STITCH FORMl NG MECHANISM FOR SEWING MACHINES. APPLICATION FILED 8.7.1920. RENEWED JUNE 1, 1921.

3 7 144 Patented Aug. 9, i921 4 sHEETs-sHEEf 1 INve NTor- James JL. iamaqaw.

:A'H'JA :I. A. FLANAGAN.

STITCH FORMING MECHANISM FOR SEWING MACHINES. APPLICATION FILED FEB. 7. I920- RENEWED JUNE I. 1921.

[,387, 1 4% Patented Aug. 9, 1921.

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J. A. FLANAGAN. STITCH FORMING MECHANISM FOR SEWING MAUHINES. APPLICATION FILED FEB. 7. I920. RENEWED JUNE 1. I921.

1,537,144. F Patented A g. 9,1921

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J ame A. Flanagan 1; A. FLANAGAN. STITCH FORMING MECHANISM FOR'SEWING MACHINES.

APPLICATION FILED FEB. 7, I920. RENEWED JUNE 1. I921- 1,387, 144. Patented Aug. 9, 1921.

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. lNveNror, I James A Flanagcwv dut STITCH-FORMING MECHANISM non SEWING-MACHINES.

Application filed February 7, 1920, Serial No. 357,017.

To all whom it may concern-.-

Be it known that I, JAMES ALEXANDER FLANAGAN, a British subject, residing at the city of Toronto, in the county of York and Province of Ontario, Dominion of Canada, have invented certain new and useful Improvements in Stitch-Forming Mechanism for Sewing-Machines; and I hereby declare the following is a full, clear, and exact description of the same.

This invention relates to a stitch forming mechanism for sewingmachines comprisin a stationary thread case having a segmenta peripheral flange with a loop holder at one extremity, and a loop taker formed with a thread case cavity, in which the thread case' is journaled, and consisting of an assembly plate having segmental cylindrical flange on its inner face formed with. a peripheral shoulder, a cylindrical body member mounted on the cylindrical flange having a channel toreceive the peripheral shoulder, and asegmental frusto-conical' loop deflector formed at its forward end with a single beak arranged obliquely to the periphery of the thread case, and moving in rear of the needle path, for entering the loop, drawing it through the needle eye, and passing the needle side of the loop around the back of the thread case, the beak having a thread race extending from its heel to the deflector for directing the work side of the loop across the frusto-conical surface to the front side of the deflector and imparting the twist to the loop as it moves across the front of the thread case, and, an internal annular flange within the deflector opposed to the flange of the assembly plate and forming with it a raceway for the peripheral flange of the thread case.

For an understanding of the invention reference is to be had to the following description and accompanying d'fiiwings, in which: I

Figure 1, is a side view of the stitch. form ing mechanism showing the position of the parts when the beak of the loop taker is about to enter the loop,

Fig. 2, is an end view of the same showing the position of the parts when the beak has ente'ed the loop.

Fig. 3, is an end vicw'oi the stitch forming mechanism showing the position of the parts when the loop holding member isabout to engage one side of the loop,

Specification of Letters Patent.

ing

the loop across the front of the thread case,

Patented Aug. 9, 1921. Renewed .Tune l, 1921. Serial No. 474,303.

Fig. 3 isa side view showing the parts 1n the same pos1tion as inFig. 3,

Fig. 4, is an end view of the stitch forming mechanism showing the position, of the parts when the loop, holding member has entered the loop and the loop taker is about to pass the needle side of theloop behind the thread case. I Fig. 4 is a side View showing the partsof the stitch forming mechanism inv the same position as in Fig. 4,

Fig. 5, is an endview of the parts show-f the loop taker passing the work side of Fig. 5, show- Fig. 6, is a similar view to the take up,

ing the delivery of the loop for Fig. 7, is a sectional view taker,

Fig. 8, is an end view of the loop holdinginember, l

' Fig. 9, is a member,

Fig. 10, is an end view of the thread case, F lg. 11, is a top plan View of the thread case, Fig. 12, is an elevational view of the thread case,

Fig. 13, is a sectional view showing the assembly of the bobbin and the thread case, the latch in'this case being released from the axial pin, i

Fig. 14, is a similar View to Fig. 13, showing the latch engaged with the and released from the bobbin,

Fig. 15, is a detail view of the latch, Fig. 16, is a sectional detail view of the assembly plate, i Fig. 17, is a sectional detail viewof assembly plate taken. at right angles to Fig. 16, and Fig. 18, is a diagrammatic view of a twisted lock stitch. Like characters of reference refer to like parts throughout the specification and drawings. I

Incorporated in the construction of the stitch forming mechanism is a segmental cylindrical assembly member, comprising a circular assembly plate a, having a central, boss 7) projecting beyond its rear face to reccivc the loopcr shaft, the peripheral surface of the boss having a cam c, which imparts arise and fall movement to the feed dog.

The inner side face of the assembly plate axial pin of the loop 7 the i a has a segmental flange 05 concentric with its axis, the space d, between the ends of the flange being approximately equal to onethird of the circumference of its circle to provide a sufficient clearance for the reciprocation of the needle.

' The outer diameter of the segmental flange (l, as shown in Fig. 17, is slightly less than the diameter of theiassembly plate, to form with it a peripheral shoulder c; and in the flange d are diametrically opposed screw threaded holes f.

The loop taker comprises a cylindrical body section or ring 9, which snugly fits on the segmental flange when assembled with the plate a, the inner surface of the ring having a circular groove in adjacent to its rear edge to receive the peripheral shoulder 6. holes g alined with the screw threaded holes f and passing through the clearance .holes 9, and entering the screw threaded holes f are machine screws 2', securing the plate a, and the loop taker together. The periphery of the ring 9 is cut away for about one-third of its circumference, as shown at j, and this cut away part is alined with space (1 in the segmental-flange (l to also provide a clearance for the needle.

Integrally formed with the ring at one side of the cut away part 7', is he beak Z, which moves in a circular path in rear of and adjacent to the vertical path of the needle 7c.

The beak, as shown in Fig. 2, is located at the right of the cut away part j with its point m directed to the left. The rear side Z of the beak is oblique to the face of the ring to form with its peripheral surface, a heel O. The heel of the beak is rounded and the peripheral surface of the ring is beveled from the heel of the beak toward the the stationary hook a and thus insure. the

stationary hook engaging the bottom 77 of the loop when the rotary loop taker carries the loop to it.

integrally formed with the front face of 1 the ring 9 is a segmental frusto conical loop deflector f extending from the rear of the beak Z partially around the ring to the opposite side of the cut away part Within thebore of the rin g is an annular flange a which in conjunction with the flange (7 forms a race for the stationary hook The stationary hook 8 consists of a seg- In the ring 9 are clearance,

mental flange or rib integrally formed with or secured to the; peripheral surface of the cup shaped body section r of the thread case, and when the parts are assembled it abuts against and is contained between "and main tained in position by the flanges Z and u. The body section I! is provided with an internal axial pin 4) having a groove 41 near its outer end to receive the latch in ofithe cap section 00 of the thread case. The rim of this body section is provided with a bifurcated projecting lug, the forks 7 ;z of which are separated by an intervening slot 1 forming the path for the needle It The needle and shuttle threads for the stitch pass upwardly through the slot y and are maintained in position by the forks 2 1 The fork y as shown in Figs. 1 to (3 inclusive has an upturned end 3 which is engaged by a holding member y conveniently secured to the bed plate of the machine to prevent the rotation of the thread case. The cap section of the thread case is also of a cup shaped formation and its cylindrical wall 2 is formed with a needle hole 2 alined, when the parts are assembled, with the slot y.

The periphery of the cylindrical wall as shown in Fig. 11, is formed with a segmental rib or flange a, the ends of which are separated by an intervening space .2 to receive between them the forks 1 7 which when entered therein engage the ends of the rib or flange (4 and hold the cap section against rotation and thus maintain it in its fixed relation with the body section 7) and the other parts of the stitch forn'iing mechanism, with the needle-hole 2 in correct alinemcnt with the slot ;2 The cylindrical wall 2 of the cap section fits snugly within the body section 01 and is not only maintained in a fixed position with relation to the body section by the engagement of the ends of the segmental rib or flange a with the forks y, but is brought by this means into correct relation with the body section, when being assembled, the space between the ends of the segmental rib or flange, providing a clearance sufficient only for the forks 3 of the lug, and the rib or flange a being of such depth as to engage the ends of the forks 3/, 3 and prevent the assembly unless this clearance comes into correct alinement with them.

When the cap section 00 is assembled with i the body section o, the edge of the cylindrical wall 2 abuts against the inner face of the side or end wall 7) of the body section n and in conjunction with the body section completely incloses the bobbin 7), thus constituting the thread case.

The cylindrical wall 2 is rovided with a slit 71 for the bobbin threat 2 this slit 6 extending obliquely in an upward direction from the inner to the outer edge of the cylindrical wall 2. Overlying the outer-upper part of the slit is the free end of the tension spring 0, the other end of the spring being suitably secured to the cap section as. In the side or end wall a" of the cap section is a thread channel 0" extending transyersely across it in line with the upper end of the slit 6 and secured to the outer or end wall a" above the thread channel 0" is'a flat plate d", the end of which is formed with an inclined slot 03 terminating in the thread de livery aperture d In the outer face of the end wall a is a slideway eparallel with the channel a and movable in this slideway is a slide member e". The slide member 6 has a lateral lug f overlying the end of the slideway e, and this lug is pressed by a spring f" seated in a chamber i formed in the end wall a the endwall having a cut away part g for the movement of the lug f. The slide member 6" has a hooked shaped lugg extending lengthwise of the axis of the cap section and overhanging the 'edge of the end wall a.', the cylindrical wall 2 being formed with an aperture 2" for the movement of the lug g and for the entry of its hook shaped end 9 into the bobbin holding member.

Formed centrally through the slide member e and the end wall a" is abore z'" for the axial pin 4), and extending into the bore 2'" from the slide member e is a latch w'to enter the groove 41' of the pin 1) when the slide member is pressed by the spring f.

Secured centrally to the end-wall a and extending into the cap section is an internal sleeve 7', the bore of which is in axial alinement with'the bore z'", to inclose the inner part of the axial pin a, and provide a journal for the bobbin b, the outer extremity of the sleeve 9'" terminating at the-inner face of the end Wall a" to leave that part of the axial pin 41 within the bore of the slide member 0" exposed so' that the latch on can enter the groove '0'.

In assembling the bobbin 6 in the thread case, the'hub b of the bobbin 6' is placed upon the sleeve 9'" and the outer flange b of the bobbin is engaged by the hook g of the lug 9 the hook shaped lug then securely holding the bobbin correctly positioned within the cap section a: while the bobbin and cap section are being assembled with the body section '1). In threading the machine the bobbin thread 2 is entered in the inner end of the slit 5 and drawn through the latter, under the free end of the tension spring 0', along the thread channel 0'', under the end of the flat plate (1", through thd inclined slot (i to the thread aperture (1 The cap Section with the bobbin is then assembled in the body section 0 by placing the sleeve j" on the axial ,pin o with the spacebetween the ends of the segmental rib or flange 0' in line with the forks y, y, the slide member 6" during this assembly being manually pressed to maintain the lug g in engagement with the outer flange of the bobbin and securely hold it in position with the cap section, the latch w then being clear of the pathof the axial .pin v. v 7 When the manual pressure on'the slide member is removed. the spring f" presses it,rand ,disengages the hook shaped lug g from the bobbin flange and at the same time causes the latch to to enter the groove of of the pin 1; and lock the cap section and the body section of the shuttle or thread case together.

In separating the cap section from the v body section the slide member e" is pressed to release the latch to from the groove '0'" and bring the hook shapedlug 9 into en'- gagement with the outer flange of the bobi- 1n, thereby releaslng the cap section from the body section and temporarily locking thebobbin Within'the cap section. The cap section and bobbin can then be withdrawn from the body section. I

In Fig. 1', of the drawings the needle k" is shown to be receding; and the loop m is shown to be formed and the the beak Z is about to enter it. In Fig. 2, the beak has entered the loop and is about to carry" it forward to the stapoint in of tionary hook s for the formation of the stitch In Fig. 3, the beak Z is shown to have carried the r'earside p of the loop past the stationary hook s, and the bottom 19 of the loop is shown to be engaged and held by the stationary hook agalnst farther travel, until the loop is ready to be delivered for the take up. At this stage the work side 12 of the loop is seated at the heel of'the beak I which is so positioned as to be always,

within the plane of the rear face of the body section of the thread case during the revolution of the loop taker, and as there is no contact between the thread case and the remainder of the stitch forming mechanism. other than the peripheral rib and terminating in the stationary hook within the raceway provided for it, the beak can pass the needle side of the loop freely across the back of the thread case during the revolution of the loop taker. When the heel of the beak passes the stationary-hook, the work side of the loop is behind the thread case, and as the beak continues its rotation the thread race-0' positively passes the work side of the loop on the frusto-conical surface of the loop deflector which passes the work side of the loop to the front of the thread case, as shown in Fig. 5, this movement continuing until the stationary hook is exposed by the cut away part j coming into line with it for the shedding of the loop prior to the take up.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a sewing machine, a stitch forming mechanism comprising a stationary thread case having a peri heral loop holder, and a rotary loop taker ormed with a thread case cavity in which the thread case is journaled, and with a segmental frusto-conical loop deflcctor, partly encircling the thread case, having at its forwardend a single beak moving in rear of the needle path, for entering the loop, drawing it through the needle eye, and passing the needle side of the loop across the back of the thread case, the beak having a thread ,race for directing the work side of the loop. on the loop deflector to be passed by it across the front face of, the thread case durin the revolution of the loop taker.

2. 1%. a sewing machine, a rotary loop take! for the stitch forming mechanism comprising a segmental cylindrical assembly member, a cylindrical body member mounted thereon, a. segmental frusto-conical loop deflector for the body member, and a single beak at the forward end of the deflector, having a thread race to direct the work side of the loop on the frusto-coniq'al surface of the deflector to be ipassed across the front face thereof during the revolution of the loop taker.

3. In a sewing machine, a stitch forming mechanism comprising a stationary thread case having a peripheral segmental flange,

in combination with a loop taker formed with a thread case cavity in which the thread case is journaled, and comprising an assembly plate having a segmental cylindrical flange, a cylindrical body member mounted on the cylindrical flange having a segmental frusto-conical loop deflector formed at its forward end with a single beak having a thread race for directing the work side-of the loop on the deflector, and, an internal annular flange within the deflector opposed ,to the flange of the assembly plateqandi forming with it a raceway for the peripheral flange of the thread case. a

4. In a sewing machine, a loop taker comprising a circular assembly plate having a segmental annular flange formed with a peripheral shoulder, a cylindrical body section mounted on the flange and formed with. an annular channel, to receive the peripheral shoulder, and having a segmental frustoconical loop deflector, a single beak at the forward end of the loop deflector formedwith a thread race for directing the work side of the loop on the fIllStOx-COIllOflgl surface. of the deflector, and an internal annular flange within the deflector opposed, to, the flange of the assembly plate.

Toronto, Ontario, January 29th, 1920.

JAMES ALEXANDER FLANAGAN.

Signed in the resence of CHAS. H. IGHES, W. J. GILoHnIs'r. 

